Close editor on quit

src/main.rs

@@ -111,6 +111,7 @@ fn main() -> Result<ExitCode> {
             };
 
             watch::watch(&mut app_state, notify_exercise_names)?;
+            app_state.close_editor()?;
         }
         Some(Command::Run { name }) => {
             if let Some(name) = name {

src/watch.rs

@@ -172,8 +172,7 @@ pub fn watch(
     watch_list_loop(app_state, notify_exercise_names)
 }
 
-const QUIT_MSG: &[u8] = b"
-
+const QUIT_MSG: &[u8] = b"q\n
 We hope you're enjoying learning Rust!
 If you want to continue working on the exercises at a later point, you can simply run `rustlings` again in this directory.
 ";